Among the demonstrators advocating for a federal jury to spare the life of Dzhokhar Tsarnaev – the convicted Boston Marathon bomber – are a group of military veterans who oppose capital punishment.

Joe Kebartas, a 66-year-old South Boston retiree who served as a medic in the Vietnam War, was among those demonstrating outside the courthouse Tuesday, where the sentencing phase of the trial began. A just sentence, said Kebartas, who was among those from the group Veterans for Peace to demonstrate on Tuesday, would be life without parole.

“That’s a just penalty for the horrific crime he did,” he said.

He added, “Every life is important. The only one who has the right to take a life is God. Not our government.”

Winston Warfield, 68-year-old Vietnam vet from Dorchester said he demonstrated against the death penalty because he wants Bostonians to “get more interested in peace.”

“I’m opposed to the death penalty in any circumstances, on moral and ethical grounds. More importantly to me, I’m trying to get a discussion between this crime of terrorism and war and peace,” said Warfield.

Warfield said the marathon bombings were an example of “blowback” meaning the blasts were the fruits of hawkish American foreign policy that included drone strikes and assassinations various countries around the world.

“We Americans should be more serious about insisting on peace by our government,” he said. “We are now getting caught up in this insanity.”

Michael Sullivan, a 30 year-old self-employed handyman who lives in Shirley and did a tour of Iraq during his stint in the Army from 2005 to 2007, said he understands what Tsarnaev did, why he did it and that he should be penalized but added, “I don’t think the death penalty should be given to someone that young.”

“I’m for peace,” said Sullivan, who is a member of Veterans for Peace, when reached by phone early Tuesday afternoon. “I’m for the fact that everyone has a right to live.”